Arianespace Ariane 5 rocket is set to launch ESA-JAXA Mercury mission BepiColombo on October 19 from Kourou, French Guiana spaceport. Upon arrival at Mercury on 5 December 2025 after 9 gravity assists, the craft comprised of 3 major components will separate into 2 satellites: Mercury Planetary Orbiter built by ESA, and Mercury Magnetospheric Orbiter (also called Mio “waterway” or “fairway”) built by JAXA. The mission will work to map gravity and magnetic fields, characterize Mercury liquid iron core which is an estimated 3⁄4 of the planet’s radius, verify water ice in polar craters, and investigate its exosphere. There was to be a 44-kg Mercury Surface Element lander which was canceled due to budgetary restraints. Among Mercury’s unique properties it has the greatest temperature swing in the Solar System at 600°C, fastest orbital period of 88 Earth days, may contain ‘younger than expected’ water ice, formed very early in Solar System history and might be tectonically active. ESA is operating interplanetary craft Mars Express and ExoMars 2016, while planning for ExoMars 2020 and Jupiter explorer JUICE. JAXA is operating Akatsuki at Venus, Hayabusa2 at asteroid Ryugu, and developing lunar mission SLIM and ...